Comment 2 for bug 1288048

Though bug 1232558 has a proof of concept and some bits and pieces of ideas it's still blocking on three points:
- There's no universal way of knowing whether to enable the headerbar/titlebar - Midori is cross-platform, it can't enable it when running on a system where nothing else uses headerbars and the theme may not even support it. Not sure how valid that is for the other apps affected here.
- The design is still unclear - Epiphany seems to accept that the urlbar is very small as a side effect of being inside the header. That to me is a big concern.